Metallurgy of zinc.



F. L. GLBRG.

METALLURGY 0F ZINC.

APPLICATION FILED APR-24, 1911.

1,002,037, Patented Aug. 29, 1911.

WITNESSES: I INVENTOR w e/ ATTORNEYS FRANK LAURENT CLEBC, OF BOULDER, COLORADO.

METALLURGY 0F ZINC.

Specification of Letters Patent.

Patented Aug. 29, 19111.

Application filed Apri124, 1911. Serial No 622,978.

To all whom it may concem:

Be it known that I, FRANK L. CLERC, a citizen of the United States, residing at Boulder, orado, have invented certain new and useful Improvements in theMetallurgy of Zinc; and I do hereby declare thefollowing to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to certain new and useful improvements in the metallurgy of zinc, and particularly to the furnace reduction of zinc oxid and the distillation of the metal, preliminary to its ultimate recovery as spelter.

The invention comprises broadly the fun damental and characteristic features of supplying the zinc oxid to be reduced, to-

gether with the necessary amount of reducing material for making the customary charge, to the upper surface of a trapped body of molten metal forming the bottom of the retort or muffle and extending outside of the retort chamber to form an open Well which counterbalances the body of molten metal Within the retort, and which is heated'in any way suitable for maintaining the. metal in the molten condition,,during the reduction of the zinc oxid and the distillation of the zinc.

The metal chosen for the purpose of forming'the liquid bottom for the retort or I nfufile will be of a melting point and conductivity to heat appropriate to insure the proper temperature conditions for the desiredv reduction and distillation within the retort. It will form an effective seal against the entry of oxidizing gases into the retort and also against the from the retort. In the accompanying drawing, Figure 1 represents a cross-sectional view of one form ofapparatu's suitable for the practice of my invention; Fig. 2 represents a longitudinal sectional view on a plane indicated by the line- 2 2 of Fig. 1; Fig. 3 represents a cross-sectional view on a plane'indioated by the line 33 of Fig 1.

Similar letters of reference indicate similar parts throughout the several views.

Referring to the drawing, indicates the main furnace structure, provided with a retort or mufile chamber at, and a heatin chamber 12 adjacent thereto and separate county of Boulder, State of Col-' escape of zinc vapor to the art.

The bottom of the retort or muflle consists of a trapped body of molten metal f terminating within the heating chamber 6 in an open well, as shown, thereby sealing the retort and counterbalancing the molten metal trapped therein. The molten met-al may conveniently consist of an alloy, having a melting point higher than the temperature (1040 O.) at which zinc is reduced from its oxid by carbon. A suitable alloy for the purpose would be an alloy of zinc and copper, an alloy of Zinc and aluminum, or, in some cases, a,ternary compound, the composition "of the alloy to be chosen according to the particular circumstances of the case and particularly according tothe temperature conditions to be realized in the retort.

The liquid metal constituting the bottom of the retort may, be maintained in the molten condition, as hereinbefore indicated, in any suitable manner, by the heating ef- "fectof the electric current or by the combustion of fuel. When, for instance, the electric current is employed as the heating agent, it may be supplied as in the simple resistance furnace,the electric arc furnace, the combined arc and resistance furnace, or some modification of the induction furnace. When fuel is employed as'the agent for heatingthe met-alf-rt may be used as solid fuel burned upon a grate, sprayed hydro-carbons or pulverized coal with an air jet, natural gas with heated air, or artimufiie is provided ficial gas with heated air as in the Siemens system of double In the drawing, I havochosen as an illustration of the eferred practice, the application of the a'r and gas 'recuperators C and D as shown in Fig. 2 to the heating of the combustion chamber 6. The preheated air and preheated gas from the air recupera tor C and the gas recuperator D, respectively, (both of which have 1 the usual checker-work filling of refractory brickwork) are delivered through the air ports m and gas ports a and the resulting products of combustion pass overgthe upper surface of recuperation.

the open well, "finally 'making their exit trapped body of through the corresponding pair of recuperators at the other end of the combustion chamber, as will be readily understood, the direction of the flow of air and gas and consequently of the products of combustion being reversed from time to time in accordance with the customary practice of operating recuperator furnaces.

The higher metal values present in the charge will be recovered in the molten metal bottom, and the slag or scoria will be removed from the retort or mufiie in any suitable manner. The zinc vapors resulting from the reduction of the zinc oxid and the distillation of the zinc, will pass through the port (1 and will be recovered as spelter in a condenser, while the accom anying carbon monoxid will be burned or any useful purpose, after washing from itany blue powder and zinc oxid it contains.

In the Belgian and the Silesian practice, the heat required to expel the zinc is conducted to the charge, from without through the inclosing walls of the retort. I retain this distinctive advantage, keeping the charge isolated within its retort or muffle walls, and transmitting the heat to it, from without, through the trapped molten metal constituting the bottom wall.

Having thus described my invent-ion, what I claim is:

1. The method of reducing zine oxid by carbon and recovering the resulting zinc vapors, which consists in establishing a molten metal in the bottom of a retort, said trapped body of metal terminating outside of the retort in an outer well, supplying a charge of zinc oxid and carbon to the surface of the trapped portion within the retort, heating'the metal in the outer well, and reducing the zinc oxid of the charge bythe carbon by means of heat conducted from the well through said molten metal, to the surface of ,the ortion trapped within the retort; substantia ly as described.

'2. The method of reducing zinc oxid by carbon and recovering the resulting zinc vapors, which consists in establishing a trapped body of substantially quiescent molten metal in the bottom of a retort, said ducted from the well through trapped body of molten metal terminating outside of the retort in an outer well, supplying a charge of zinc oxid and carbon to the surface of the trapped portion within the retort, heating the metal in the outer well, and reducing the zinc oxid by the carbon of the charge by means of heatconsaid molten metal, to the surface of the ortion trapped within the retort; substantit lyas described.

3. Apparatus for reducing zinc oxid by carbon, comprising a retort, closed at its bottom'by a trapped body of substantially quiescent molten metal terminating in a well exterior to the retort, and means for supplying heat to the metal in the well sufficient to maintain the trapped metal in a molten condition by conduction; substantially as described;

4. Apparatus for reducing zinc oxid by carbon, comprising a retort, closed atits bottom by a trapped body of substantially quiescent molten metal terminating in p a well exterior to the retort, a heating chamber inclosing the well, and means for applying heating gases to the upper surface of the metal in the well; substantially as described.

5. Apparatus for reducing zinc oxid by carbon, comprising a retort, closed at its bottom by atrapped body of substantially quiescent molten metal terminating in a well exterior to the retort, a heating chamber inclosing the well, and means for directing fuel in combustion across the upper surface of the metal in the well; substantially as described.

6. Apparatus for reducing zinc oxid by carbon, comprising a retort, closed atits bottom by a trapped body of substantially quiescent molten metal terminating in a well exterior to the retort, a heating chamber inclosing the well, and recuperators for supplying gas and air to the chamber for combustion therein; substantially as described.

In testimony whereof I afiix my signature, in presence of two witnesses.

FRANK LAURENT CLERC. Witnesses: I

E. L. MERRIMAN,

D. R. MCNAUGHTON. 

